Why Fiber Deep?

Typical consumers are no longer satisfied with basic broadcast video and data services. Today they want high-definition television (HDTV), Video on Demand (VoD), higher speeds for data services, and sophisticated voice offerings. To successfully provide these services, cable operators need greater network capacity. But "capacity at any cost" is not the answer — in today's economic environment it is crucial to invest prudently in network infrastructure, showing a healthy, timely return on investment. If Fiber Deep Hybrid Fiber/Coax (HFC) is the architecture of tomorrow (as indeed it is), it is also the preferred network architecture of today's MSOs, extending optical fiber to nodes in the network that are within a few hundred feet of the subscriber's home and eliminating the need for cascades of RF amplifiers. More importantly, this architecture can be built with minimal fiber investment; MSOs typically only need to lay new fiber from existing node locations to new Fiber Deep node locations, resulting in hundreds of feet, not miles, of new fiber that is required for many other architectures (i.e., fiber-to-the-premises, or FTTP). Significantly, Fiber Deep interoperates with all existing traditional HFC components such as installed set-top boxes and DOCSIS^®/EuroDOCSIS cable modems.

A comparison of the typical network capacity of a traditional HFC network, as installed today, with a Fiber Deep architecture is shown in Table 1.

With Fiber Deep, there is 500% more downstream bandwidth and 1,000% more upstream bandwidth available — bandwidth that can be immediately used to increase service offerings.

What is Fiber Deep?

The advent of Fiber Deep architecture offers many advantages beyond that of increased bandwidth for the cable TV industry, among the more important being:

• Reduced operating costs associated with equipment installation, network maintenance, power consumption and simplified hubs
• Increased network availability and improved network performance
• Digitized return transmission technologies to support the transport of both legacy upstream services and future Ethernet-based services.

Fiber Deep is all about driving fiber deeper into the network, typically within a few hundred feet of subscribers' homes. With the optical nodes in a Fiber Deep architecture installed deeper in the network (by comparison with traditional HFC networks), the optical-to-electrical conversion of downstream signals occurs much closer to subscribers' homes and RF amplifiers are no longer required. Because the lengths of coaxial cable runs in the distribution network are shortened, this portion of the network becomes entirely passive. Additionally, this consequential reduction in the size of the node service areas also results in an increase of the narrowcast bandwidth available to individual subscribers.

The return upstream signals (5–45 MHz for North America and, for example, 5–65 MHz for other markets) are digitized at each optical node. The digital return paths from multiple optical nodes can be linked together in a daisy-chain configuration that shares a return digital transmission channel and reduces the cost of the optical transport. This digital channel can be used to support the transport of digitized upstream services, point-to-point Ethernet services, or a combination of the two. The number of nodes linked is dependent on the requirements of the services the network operator is providing.

Recent technology developments have made Fiber Deep the optimal architecture for most MSO network upgrades today:

• High-level RF node outputs
• Advanced digital return technology
• Higher-power, lower-cost transmitters
• Temperature-stable optical field couplers
• General cost reductions in optical components

Operational Considerations of the Fiber Deep Architecture

To further aid comparison between traditional HFC and Fiber Deep designs, Aurora analyzed a 20,000 HP sample area. Notable results, including operating costs, are summarized in Table 2.

Power operating costs consider both the number of power supplies required (with less than half the number needed for Fiber Deep than for HFC) and associated annual and fault maintenance costs. Maintenance costs include any troubleshooting visits to field actives together with annual maintenance visits.

In the example study, the operating cost per home for power and maintenance is reduced by 65% in the case of Fiber Deep — equivalent to ~$5 per HP/year. Eliminating RF amplifiers from the design results in approximately 70% less total active devices needed for the network. And associated with this is a 50% reduction in power supplies, resulting in a 50% savings in power costs and a significantly reduced "carbon footprint." Fiber Deep is the "green" architecture for cable operators.

Reducing the number of homes per node and exploiting Aurora's embedded element management capabilities results in a further benefit: much easier identification of fault location in the network. In a traditional HFC deployment the location of a fault is much more difficult to pinpoint; it can be anywhere within a much wider area. Ultimately, Fiber Deep significantly reduces the Mean Time to Repair for an identical fault given a reduction of the time required for the engineer to find the fault's location. (And, of course, with fewer homes connected to a node, fewer subscribers are affected by an outage in any event.)

Fiber Deep Deployed, Now What?

Fiber Deep is truly a future-proof architecture. Leveraging the capabilities of the Fiber Deep node, Aurora has developed next-generation application modules for our nodes to enable MSOs to further increase the capacity of their networks, each module customized for a specific target audience. These modules and solutions are briefly described below.

Fiber on Demand™

Point-to-point full duplex Ethernet transport capabilities are fully integrated with Aurora's digital return. The Aurora Fiber Deep architecture lends itself very well to scenarios where MSOs initially will deploy only the digital return services for the residential network and add Ethernet transport services over the same fiber span at a later date for commercial customers. This capability, for which Aurora coined the term Fiber on Demand, enables MSOs to reap additional revenues by providing Ethernet transport services to businesses, schools, government campuses and similar organizations that are located within the serving area footprint. Today it is reliably estimated that nodes pass more than 70% of SMBs/SMEs in the United States. This target market is the "sweet spot" for MSOs. With the node within just a few hundred feet of these businesses, an MSO simply needs to pull new fiber over this short distance, install the CPE equipment, and activate the special unit for the node (each node unit capable of supporting up to four businesses, each with dedicated 100 Mbps Ethernet services).

In addition, Fiber on Demand can be deployed to residential subscribers who want a higher-speed data service or who may, for example, wish to consistently exceed the data transfer limits which may be imposed by an MSO. This provides a cost-effective way for them to receive the service that they demand and for which they would ultimately pay.

Node PON™

Aurora Network's Node PON, solution features a module designed to work in all Aurora NC4000 series nodes: the GE4132M. This module enables GEPON functionality in our nodes so that cable operators can cost-effectively add all-IP services to their networks on a node-by-node basis, operating in parallel with traditional cable TV services. Ultimately, but only if and when it is justified by revenue growth, Node PONs can enable full migration of an installed HFC network to a standards-based GEPON FTTP network.

Today, a Fiber Deep architecture using a traditional coaxial cable drop to the home provides significant bandwidth, giving the cable operator a unique advantage. However, there will be some situations (i.e., rural markets) where an FTTP solution may be preferred. The GE4132M module permits a cable operator to migrate to a FTTP network by simply dropping one of these Node PON modules into an installed Aurora node and then running fiber through the community. This solution eliminates the need for an operator to re-engineer the network, ensuring protection of the investment in the installed infrastructure

Back to top